1. Field of the Invention
The present invention relates to an electronic flash apparatus, and more particularly to an electronic flash apparatus in which electric power is supplied by the same power source to the voltage elevating circuit for charging the main capacitor for flash emission and to other circuits provided in the flash unit or in the camera, such as a light emission control circuit for controlling the quantity of emitted light, an indicator circuit for indicating the completion of the charging of the main capacitor, an indicator circuit for indicating whether the light emission control is in operation, an alarm circuit for indicating an inadequate setting of the flash unit etc.
The above-mentioned power source shall include a battery, a power source producing a D.C. voltage from an A.C. power supply, and a power source converting an A.C. power supply into a determined voltage by a transformer.
2. Description of the Prior Art
In a conventional electronic flash apparatus, when the voltage elevating circuit is activated immediately after the flash emission to start the charging of the main condenser, the power source voltage is temporarily reduced and noises are generated due to oscillation in the voltage elevating circuit. Such noise-bearing reduced power source voltage is often insufficient for driving the light emission control circuit or other related indicator circuits, or induces unstable function therein.
In order to prevent such drawbacks, it is already proposed to completely interrupt the charging of the main capacitor during a determined period, for example from the flash emission to the operation of indicating whether the flash emission control is in proper operation. Such method is however associated with a drawback of inevitably prolonged recycle time from the flash emission to the completion of charging of the main capacitor.